Java Utililty Methods Collection to Array

List of utility methods to do Collection to Array

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Description

The list of methods to do Collection to Array are organized into topic(s).

Method

String[]toArray(Collection strings)
to Array 
if (strings.isEmpty()) {
    return EMPTY_STRING_ARRAY;
return strings.toArray(new String[strings.size()]);
String[]toArray(Collection values)
to Array 
return values.toArray(EMPTY_ARRAY);
T[]toArray(Collection c, T[] sample)
This is a replacement for Collection#toArray(Object[]) . 
final int size = c.size();
if (size == sample.length && size < ARRAY_COPY_THRESHOLD) {
    int i = 0;
    for (T t : c) {
        sample[i++] = t;
    return sample;
return c.toArray(sample);
T[]toArray(Collection collection)
Cast a collection to an array 
return (T[]) collection.toArray(new Object[collection.size()]);
T[]toArray(Collection list, Object[] type)
Convenience method for List#toArray(Object[]) to pass compiler warnings for generic typed array. 
Object[] array = list.toArray(type);
return (T[]) array;
Object[]toArray(final Collection c)
to Array 
return c == null ? null : c.toArray();
byte[]toArray(final Collection coll, byte[] array)
to Array 
if (array.length < coll.size()) {
    array = new byte[coll.size()];
final Iterator<Byte> it = coll.iterator();
int i = 0;
while (it.hasNext()) {
    array[i++] = it.next().byteValue();
return array;
int[]toArray(final Collection collection)
to Array 
if (collection == null || collection.isEmpty()) {
    return new int[0];
final int[] result = new int[collection.size()];
int index = 0;
for (final Integer integer : collection) {
    result[index] = integer.intValue();
    index++;
...
String[]toArray(final Collection collection)
to Array 
if (collection == null)
    return null;
final String[] a = new String[collection.size()];
collection.toArray(a);
return a;
String[]toArray(java.util.Collection collection)
to Array 
String[] array = new String[collection.size()];
Iterator<String> i = collection.iterator();
int index = 0;
while (i.hasNext()) {
    array[index] = i.next();
    index++;
return array;
...